Concentration of acidic minerals



Patented Dec. 14, 1943 IUNITED STATES PATENT OFFICE v 2,336,868 CONCENTRATION OF ACIDIC MINERALS David W. Jayne, Jr., Old Day, Cos Cob, and Elmer Greenwich, Harold M.

W. Gieseke, Stamford,

Conn, assignors to American Cyanamid Company, New York, N. Y.

, a corporation'of Maine No Drawing. Application September 6, 1941,

Serial No. 409,830

. 9Claims. (c1. 209 166) The present invention relates to mineral concentrations and more particularly relates. to a new class of reagents for selectively separating acidic minerals from other ore constituents.

Still more particularly, the present invention relates to the use of isothioureas such as S-alkyl pseudo-thioureas, N-substituted S-alkyl pseudothioureas, and the salts of said pseudo-thioureas as promoters or collectors for acidic minerals in froth flotation, film flotation, stratification,

agglomeration, tabling and related mineral sepaor artificial materialscomprismg a mixture of acidic minerals with other mineral constituents are subjected to aseparation or concentration process in the presence of a promoter for the acidic ore minerals, said promoter being a product represented by the following general formula:

IIIEL-R' NH. 7 in which R is hydrogen oi an alkyl, aryl, aralkyl or alicyclic radical, or a radical such as NH O S and R is an alkyl radical includingalkyl radicals containing oxygen, sulfur or nitrogen; preferably R is an alkyl radical having 8 or more carbon atoms and less than-32 carbon atoms.

The compounds which we use in carrying out the process of the present invention may be prepared by several different methods. In a preferred'method they are prepared by reacting thiourea or an N-substituted thiourea with an alkyl halide or other alkylating agent, for example, when an alcoholic solution of approximately equimolecular quantities of thiourea and lauryl bromide are refluxed for about 6 hours. a quantitative yield of S-lauryl pseudo-thiourea hydrobromide is obtained. When an N-substiride with an tuted thiourea is' employed-instead of thiourea, such as for example N-ethyl thiourea, N-benzyl thiourea, N-phenyl thiourea, or N-cyclohexyl thiourea, guanyl thiourea, thiobiuret, .dithiobiuret or the like, for reaction with lauryl bromide under similar conditions, the corresponding N-substituted S-lauryl pseudo-thiourea hydrobromide is obtained. Instead of lauryl bromide We may use other alkylating agents such as actyl iodide, myristyl chloride, ce'tylchloracetate, lauroy'l-amino ethyl acetate, chlormethyl myristyl ether, B-chl'or ethyl palmitate etc.

Our reagents may also be prepared by aproc-, ,ess' which comprises reacting thiourea hydrochloride or an N-substitute'd thiourea hydrochloleast 8 carbon atoms and preferably. not more i than 32 carbon atoms. Itis an advantage, how- I ever, that relatively crude mixtures of such alcohols produced by catalytic methods from hydrocarbons may be employed. Similarly in the process heretofore, crude mixtures of allzyl halides may be employed.

Still another method for preparing our reagents is one in which cyanamide is reacted with'a case the mercaptan should mercaptan. In this be one containing 8 or more carbon atoms.

Representative compounds that may be used in the present invention includethe following:

S-octyl pseudo thiourea hydro-iodide S-lauryl pseudo thiourea hydro-bromide S-myristyl pseudo thiourea hydro-chloride S-cetyl pseudo thiourea hydro-bromide S-lauryl pseudo guanyl thiourea hydro-bromide S-lauryl mono-pseudo dithiobiuret S-lauryl aceto pseudo thiourea hydrochloride 8- (N -lauroyl-amino ethyl aceto) -pseudo thiourea hydrochloride S-lauryl pseudo N-phenyl thiourea hydrobromide S-lauryl methoxy pseudo thiourea hydrochloride alcohol and in most instances the alcohol employed should be one'containing at The reagents of the present invention are efieccharged or acidic ore materials generally and a minor proportion of the ore rather than me-' tallic and sulfide ores in which the gangue usually A tive promoters or collectors for. negativelyv employed in the form of aqueous solutions, emulsions, mixtures, or solutions in organic solvents,

I such as alcohol and the like. The reagent may beintroduced into the ore pulp prior to the actual concentration operation. They may also be stag fed intothe flotation circuit.

Other improvedphosphateflotation features which are known may be utilized in connection represents the major proportion of the'ore. Rep- T "resentative acidicore materials are the feldspars,

quartz, pyroxenes, the splnels. biotite, muscovite,

clays, and the like.

with the present invention such as splitting the phosphate flotation feed into a plurality-oi size ranges and floating each size separately. as described in the U. S. Patent No. 2,156,245, the very complete removal of the slime prior to flotation which is also an aid to better results as pointed While as stated heretofore, the present invenout in the Erickson application, Serial No. tion is not limited to the treatment of any par- 325,011, filed March 20,1940, and the Mead and ticular ore material, it has been found to be wel1- Maust application Serial No. 320,121, filed Febsuited for. froth flotationof silica from phosruary 21, 1910, which describes a process for phate rock andii'sYthe preferredembodiment of classifying and desliming, phosphate I flotation the invention. iIn the processes ,of removing feed bymeans of a hindered settling .classiiier silica from phosphate rock, the conditions are and which deslimed feed is well suited fortreati such that practically :complete removal of the ment in'accordance with this inventionsilica must bea'ccomplished in order to produce This invention will be further illustrated by a salable phosphate material. Itis therefore, the following specific tests which are illustrations an advantage of'this invention that our reagents ofthe preferred embodiments thereof, butds not not only effect satisfactory removal of the silica to be strictly limited thereby.

'; but are also economical in amountsused, The A' series offlotation tests wer made ona lsamquantities required range from, 0.2 pound per ton D Ofp ph Ore from the 01d l ylm n of ore depending'uponxthe particular ore-and nearBrewster, Florida. In these tests the P the particular reagent. The invention is not, cedure was as follows:- however, limited to such quantitiea; A e f r containing 600 grams. of dry The reagents of the present invention may-be solids was conditioned for two' minutes in labora- "usedalone orinmixtures with other promoters. t y si Fas s n fl ta i a hine at 22% They may likewise be used in conjunction with solids and then 'thoroughly deslimed. The 'dc- "other cooperating materials such' as conditioning slimed sands weretransferred to the flotation reagents, 'oily. or fat materials such as hydromachi e. di ut d wi a r to give a pu carbon oils, fatty acids, or fattyacid esters. mi Solids d a e ts as shown in the 'Thesenew reagents are also adaptable for use individual tests were added. The pulp and rein any of the ordinary concentrating, processes g nts Wereconditioned flveseconds by ta such as film flotation, tabling, and particularly in 40 ing'with the airvalve-closed. Air was then infroth flotation operations. lTne ore concentrat- I troduced and the resulting concentrate froth re- 1 ingprocesses employed will depend upon the parmoved by skimming two m nutes. The results ticular type or kind of ore which is being procof the vario s e ts r shown in th table.

' Table Feed Concentrate Ta s Test I N9 wt'gr, Percent Wt. Per can a? Percent "Per cent gg Reagents insol. per cent I insol. insol. 2--- 603.9 54.54 60.01 85.35 93.91 39.99 8.31 0.00 Octyl pseudothiourea hydrobromide 5.00 lbs.

1 1 I85 r per ton, pine oil 0.24 lbJton. 3 609.0 54.54 66.50 81.10 98. 88 33.50 1.83 1.12 Lauryl pseudo-tbiourea hydrobromide 0.50 i I V z" 1 lbJton. pine oil 0.12 lbJton. 4. 613.0 54.54 a 68.35 79.31 99.39 31.65 1.05 0.61. Mgistyl pseudo-thiourea-hydrobromide 0.50 a 1 ./ton, pine oil 0.12 lb./ton.

..7. 011.7 I as. 54 70.46 75,40 97.41 29.54 4. 76 2. 59 celsfiyl'lle gsfiladlotlliogjrlea hydrochloride 0.50lb./ton,

"11-.- 606.5 54. 54 60.35 87.56 sass 'aaes 4.29 3.12 Lauryl pseudo-guanyl thlourea hydrobromide 0.50 lb./ton, pine oil 0.12 lb./ton. y

In test No. 26cm pseudo thiourea hydrobromide and pine cil added by fessed. For example, in connection with phosphate rock, relatively coarse phosphate bearing materiaL'for example, 28 mesh and larger, can be'very economically concentrated'by'using these .reagents in conjunction with a material such as fuel oil or pine ,oil and subjecting to concentrationqby the use of tables or. byfllm flotation. The 28 -phosphate rockmaterial is best concen-'- trated bymeans of froth flotation employing these improved silica promoters. I Whenthe reagents of the presentinvention stages. Total flotation time-5 minutes. 7

. An analysis of themetallurgical data in the table shows that in all tests-the phosphate product .(tails) is of satisfactory marketable grade. In the tests thephosphate product is of arr average better grade than currently producedby the flotation of phosphate particles from the silica.

--In two of the tests, 3 and 4, the percent insol. is

are employed as promoters in the froth flotation of silica from phosphate rock, which is the-preferred embodiment thereof, the condition may be varied in accordance with procedures known to those skilled in the, art. The reagent may be less than 2% and this represents a commercially high grade phosphate product. When rake classifier sands such as those produced from the taili'ngs' at the Valley iForge Cement Companyplants are treated by flotation using ourreagents, the alumina in'the form of mica, is removed in part from the silicious material and a cement product is produced which has greatly improved properties.

In the treatment of iron ores we have found that our reagents may be employed in flotation processes for removing the silica therefrom and the tailings resulting from such processes are much higher in iron content than concentrates produced by the conventional soap flotation of the iron minerals.

We claim: 7

1. In ore concentrating processes utilizing differential surface wettability principles of separating acidic ore materials from other ore constituents, the process which comprises carrying out the concentration operation in the presence of a substance of the group consisting of those represented by the following formula:

IETH-R' (6- 8-K. NH

in which R is a member of the group consisting of hydrogen, alkyl, aryl, aralkyl, cycloaliphatic,

radicals and R represents a member of the group consisting of alkyl, and alkyl groups containing oxygen, sulfur or nitrogen, and the salts of such compounds.

2. In ore concentrating processes utilizing differential surface wettability principles of separating acidic ore materials from non-metallic ore, the process which comprises carrying out the concentration operation in the presence of a substance of the group consisting of those represented by the following formula:

in which R is a member of the group consisting of alkyl, aryl, aralkyl, cycloaliphatic,

radicals and R represents a member of the group consisting of alkyl, and alkyl groups containing oxygen, sulfur, or nitrogen, and the salts of such compounds.

3. In the froth flotation process of separating acidic silicious gangue from non-metallic ore,

in which R is a member of the group consisting of hydrogen, alkyl, aryl, aralkyl, cycloaliphatic,

radicals and R represents a member of the group consisting of alkyl, and alkyl groups containing oxygen, sulfur, or nitrogen, and the salts of such compounds.

4. In the froth flotation process of separating acidic silicious gangue from phosphate ore values, the step which comprises subjecting the ore to froth flotation in the presence of a product of the group consisting of those represented by the following formula:

NH-R -sq:

in which R is a member of the group consisting of hydrogen, alkyl, aryl, aralkyl, cycloaliphatic,

NH 0 s g g -c o and 0 NH: NE: NH:

radicals and R represents a member of the group consisting of alkyl, and alkyl groups containing oxygen, sulfur, or nitrogen, and the salts of such compounds.

5. In the froth flotation process of separating acidic silicious gangue from phosphate ore values, the step which comprises subjecting the ore to froth flotation in the presence of a product of the group consisting of those represented by the following formula:

NH in which R represents a radical of the group consisting of alkyl and alkyl groups containing oxygen, sulfur, or nitrogen, and the salts of such compounds.

6. In the froth flotation process of separating acidic silicious gangue from phosphate ore values, the step which comprises subjecting the ore to froth flotation in the presence of a product of the group consisting of those represented by the following formula:

and salts of such compounds.

'7. In the flotation process of separating acidic silicious gangue fro phosphate ore values, the step which comprises subjecting the ore to froth flotation in the presence of lauryl pseudo-thicurea hydrobromide.

8. In the flotation process of separating acidic silicious gangue from phosphate ore values, the step which comprises subjecting the ore to froth flotation in the presence of cetyl pseudo-thiourea hydrochloride.

9. In the flotation process of separating acidic silicious gangue from phosphate ore values, the step which comprises subjecting the ore to froth flotation in the presence of lauryl pseudo-guanyl thiourea hydrobromide.

DAVID W. JAYNE, JR. HAROLD M. DAY. ELMER W. GIESEKE. 

